A tamper evident seal is understood to be a seal which can only be opened once and then not resealed, or which may be able to be resealed, but, in this context, does not retain its original sealed condition, so that once the seal has been opened, any subsequent sealing cannot go unnoticed. Tamper evident seals are preferably used for those containers where the user either wants to be certain or must be certain that he or she is opening it for the first time, in other words that he or she has a still originally sealed container with the contents intact. Therefore, tamper evident seals are used in particular for containers in the consumer goods industry, thus, for example, for food, cosmetics, detergents, and also motor oil. Tamper evident seals are also useful for containers used in laboratory science, for example, for preserving chemicals and samples, and containers for medical sciences, for example, containers for infusion solutions and dialyzing solutions.
The following types of tamper evident seals are known. Cut-off tip tamper evident seals, for example, as in silicon cartridges are known in the art. Typically cut-off tip tamper evident seals include a one-piece outflow connector that is sealed at one end. The connector is opened by cutting off the sealed end to expose the opening of a container.
The twisting break-off tip, e.g., as in blood-product pouches, is another type of tamper evident seal wherein a connector is formed in one piece and is sealed at one end by a section having a grippable pair of opposing twistable wings. The sealing section is joined by a concentrically disposed line of weakness to the tubular part of the connector, so that the connector can be opened by turning the grippable pair of wings such that the sealed section breaks off at the rupture joint formed by the line of weakness.
Partial break-off connectors have been used, for example, in transperitoneal dialysis pouches. In this type of tamper evident seal, the withdrawal connection of the pouch is comprised of a flexible tube into which is inserted a coupling piece of injection-molded plastic. A break-off plug projects out of the coupling piece into the tube, so that bending the tube causes the break-off plug to be broken off thereby releasing the contents of the container.
Still another type of tamper evident seal is a membrane that is capable of being pierced, e.g., as in solvent canisters. The connector is sealed by a membrane, which can be pierced by a tool, for example, by a screw-on cap having a point on the reverse side.
Tear tabs are known for use in drink cans. Such tear tabs include a predetermined breaking zone worked into the cover through formation of a circumferential line of weakness. The predetermined breaking zone is secured by a tab, so that the predetermined breaking zone is able to be released out of the cover when tensile stress is applied to the tab.
Pull-off seal membranes are known for use with food containers, e.g., yogurt containers. The membrane is secured circumferentially to the cover rim by what is known as a peelable seam. A portion of the membrane projects over the side and is used as a grip when tearing off the membrane.
Screw caps with perforated seal rings are known for use with, for example, drink bottles. Situated on the cover beneath the thread section of such a screw cap is a circumferential ring, which is joined by a perforation or another circumferential rupture joint to the cover. The ring grips with form locking in an undercut on the bottle neck. When the cover is unscrewed, the ring remains following separation of the rupture joint on the bottle neck.
Seal foil caps are known for use in, e.g., cognac bottles and water bottles. Placed over the screw-on or plug-type cover is a cap of tin or aluminum foil which is formed thereon, Another type of seal cap is a plastic sleeve which is shrunk into place. Typically, seal caps include initial tear spots or tear strips to facilate removal of the caps.
The strip seal is still another tamper evident seal known for use with, e.g., glass honey jars or tea bags. A strip-shaped piece of paper, which can be part of the label, is glued on so as to join the cover to the container and, upon removal of the cover, is torn.